1
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Hypercapnic Failure in Acute Exacerbated COPD Patients: Severe Airflow Limitation as an Early Warning Signal. J Clin Med 2022; 12:jcm12010258. [PMID: 36615058 PMCID: PMC9821585 DOI: 10.3390/jcm12010258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/23/2022] [Accepted: 12/26/2022] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Hypercapnic failure is a severe complication of COPD disease progression, which is associated with a high morbidity and mortality. The aim of this study was to examine the association of comorbidity and clinical risk factors with the development of hypercapnia in acute exacerbated COPD patients. METHODS In this retrospective monocentric cohort study, we examined the influence of the clinical parameters and the comorbidity of hospitalized patients with the acute exacerbation of COPD on the development of hypercapnia by performing multivariate logistic regression and a receiver operating characteristic analysis. RESULTS In total, 275 patient cases with COPD exacerbation were enrolled during the period from January 2011 until March 2015, where 104 patients (37.8%) with hypercapnia were identified. The logistic regression analysis revealed severe airflow limitation (decreased FEV1) as the main factor associated with the development of hypercapnia. In the ROC analysis, we determined an FEV1 of 42.12%, which was predicted with a sensitivity of 82.6% and specificity of 55%, and an absolute value of FEV1 of 0.8 L, with a sensitivity of 0.62 and specificity of 0.79 as the cut off points, respectively. We could not verify an association with the patient's condition or the laboratory surrogate parameters of organ failure. CONCLUSION Severe airflow limitation is an important risk factor that is associated with hypercapnic failure in acute exacerbated COPD patients. Validation in prospective cohorts is warranted and should focus on more intensive monitoring of these at-risk patients.
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Cummins EP, Bharat A, Sznajder JI, Vadász I. Editorial: Elevated Carbon Dioxide Sensing and Physiologic Effects. Front Physiol 2022; 13:894222. [PMID: 35574468 PMCID: PMC9092065 DOI: 10.3389/fphys.2022.894222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 03/22/2022] [Indexed: 11/21/2022] Open
Affiliation(s)
- Eoin P Cummins
- School of Medicine and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Ankit Bharat
- Division of Thoracic Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States.,Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - István Vadász
- Department of Internal Medicine, Member of the German Center for Lung Research (DZL), Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany.,The Cardio-Pulmonary Institute (CPI), Giessen, Germany.,Institute for Lung Health (ILH), Giessen, Germany
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3
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Kryvenko V, Vadász I. Mechanisms of Hypercapnia-Induced Endoplasmic Reticulum Dysfunction. Front Physiol 2021; 12:735580. [PMID: 34867444 PMCID: PMC8640499 DOI: 10.3389/fphys.2021.735580] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 10/27/2021] [Indexed: 01/16/2023] Open
Abstract
Protein transcription, translation, and folding occur continuously in every living cell and are essential for physiological functions. About one-third of all proteins of the cellular proteome interacts with the endoplasmic reticulum (ER). The ER is a large, dynamic cellular organelle that orchestrates synthesis, folding, and structural maturation of proteins, regulation of lipid metabolism and additionally functions as a calcium store. Recent evidence suggests that both acute and chronic hypercapnia (elevated levels of CO2) impair ER function by different mechanisms, leading to adaptive and maladaptive regulation of protein folding and maturation. In order to cope with ER stress, cells activate unfolded protein response (UPR) pathways. Initially, during the adaptive phase of ER stress, the UPR mainly functions to restore ER protein-folding homeostasis by decreasing protein synthesis and translation and by activation of ER-associated degradation (ERAD) and autophagy. However, if the initial UPR attempts for alleviating ER stress fail, a maladaptive response is triggered. In this review, we discuss the distinct mechanisms by which elevated CO2 levels affect these molecular pathways in the setting of acute and chronic pulmonary diseases associated with hypercapnia.
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Affiliation(s)
- Vitalii Kryvenko
- Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany.,The Cardio-Pulmonary Institute (CPI), Giessen, Germany
| | - István Vadász
- Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany.,The Cardio-Pulmonary Institute (CPI), Giessen, Germany.,Institute for Lung Health (ILH), Giessen, Germany
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4
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Ba G, Tang R, Mao S, Li Z, Ye H, Lin H, Zhang W. The Expression and Regulation of Na+-K+-ATPase in Nasal Epithelial Cells of Chronic Rhinosinusitis with Nasal Polyps. ORL J Otorhinolaryngol Relat Spec 2021; 84:139-146. [PMID: 34551419 DOI: 10.1159/000517101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/04/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Na+-K+-ATPase (NKA) is essential in maintaining cell permeability, reserving potential energy, and preventing cellular edema. Nevertheless, how NKA expression is altered and regulated in chronic rhinosinusitis with nasal polyps (CRSwNPs) remain uncertain. Therefore, the present study aimed to explore the expression and regulation of NKA in CRSwNP. METHODS NKA immunolabeling was assessed by the immunohistochemistry method, NKA protein levels were detected with the Western blotting method, and mRNA levels of NKA and aquaporin-5 (AQP5) were assayed by real-time PCR in nasal tissues from CRSwNP and control subjects. The co-localization of NKA with inflammatory cells was evaluated by immunofluorescence staining. In addition, human nasal epithelial cells (HNECs) were cultured and stimulated using various stimulators to evaluate the regulation of NKA. RESULTS We found significantly decreased NKA positive cells, NKA protein levels, and mRNA levels of NKA and AQP5 in nasal tissues from CRSwNP patients compared to control subjects, especially in eosinophilic CRSwNP. Furthermore, NKA mRNA levels in HNECs were downregulated by staphylococcal enterotoxin B (SEB), lipopolysaccharides (LPSs), inflammatory cytokine (IFN)-γ, IL-4, IL-13, and IL-1β. CONCLUSION NKA and AQP5 expressions were decreased in CRSwNP. NKA in HNECs could be suppressed by SEB, LPS, IFN-γ, IL-4, IL-13, and IL-1β. Impairment of NKA may contribute to the genesis and development of CRSwNP via inducing AQP5 downregulation and edema.
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Affiliation(s)
- Guangyi Ba
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.,Otolaryngological Institute, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Ru Tang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.,Otolaryngological Institute, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Song Mao
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.,Otolaryngological Institute, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Zhipeng Li
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.,Otolaryngological Institute, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Haibo Ye
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.,Otolaryngological Institute, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Hai Lin
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.,Otolaryngological Institute, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
| | - Weitian Zhang
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China.,Otolaryngological Institute, Shanghai Jiao Tong University, Shanghai, China.,Shanghai Key Laboratory of Sleep Disordered Breathing, Shanghai, China
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5
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Baloğlu E, Mairbäurl H. In Search of a Sensor: How Does CO 2 Regulate Alveolar Ion Transport? Am J Respir Cell Mol Biol 2021; 65:571-572. [PMID: 34348088 PMCID: PMC8641802 DOI: 10.1165/rcmb.2021-0270ed] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Affiliation(s)
- Emel Baloğlu
- Acibadem Mehmet Ali Aydinlar University School of Medicine, Department of Pharmacology , Istanbul, Turkey
| | - Heimo Mairbäurl
- University Hospital Heidelberg, 27178, Translational Pneumology and Translational Lung Research Center Heidelberg (TLRC) German Center for Lung Research (DZL) Im Neuenheimer Feld 156, Heidelberg, Germany;
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6
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Gabrielli NM, Mazzocchi LC, Kryvenko V, Tello K, Herold S, Morty RE, Grimminger F, Dada LA, Seeger W, Sznajder JI, Vadász I. TRAF2 Is a Novel Ubiquitin E3 Ligase for the Na,K-ATPase β-Subunit That Drives Alveolar Epithelial Dysfunction in Hypercapnia. Front Cell Dev Biol 2021; 9:689983. [PMID: 34277634 PMCID: PMC8283768 DOI: 10.3389/fcell.2021.689983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/09/2021] [Indexed: 11/20/2022] Open
Abstract
Several acute and chronic lung diseases are associated with alveolar hypoventilation leading to accumulation of CO2 (hypercapnia). The β-subunit of the Na,K-ATPase plays a pivotal role in maintaining epithelial integrity by functioning as a cell adhesion molecule and regulating cell surface stability of the catalytic α-subunit of the transporter, thereby, maintaining optimal alveolar fluid balance. Here, we identified the E3 ubiquitin ligase for the Na,K-ATPase β-subunit, which promoted polyubiquitination, subsequent endocytosis and proteasomal degradation of the protein upon exposure of alveolar epithelial cells to elevated CO2 levels, thus impairing alveolar integrity. Ubiquitination of the Na,K-ATPase β-subunit required lysine 5 and 7 and mutating these residues (but not other lysines) prevented trafficking of Na,K-ATPase from the plasma membrane and stabilized the protein upon hypercapnia. Furthermore, ubiquitination of the Na,K-ATPase β-subunit was dependent on prior phosphorylation at serine 11 by protein kinase C (PKC)-ζ. Using a protein microarray, we identified the tumor necrosis factor receptor-associated factor 2 (TRAF2) as the E3 ligase driving ubiquitination of the Na,K-ATPase β-subunit upon hypercapnia. Of note, prevention of Na,K-ATPase β-subunit ubiquitination was necessary and sufficient to restore the formation of cell-cell junctions under hypercapnic conditions. These results suggest that a hypercapnic environment in the lung may lead to persistent epithelial dysfunction in affected patients. As such, the identification of the E3 ligase for the Na,K-ATPase may provide a novel therapeutic target, to be employed in patients with acute or chronic hypercapnic respiratory failure, aiming to restore alveolar epithelial integrity.
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Affiliation(s)
- Nieves M. Gabrielli
- Member of the German Center for Lung Research (DZL), Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
| | - Luciana C. Mazzocchi
- Member of the German Center for Lung Research (DZL), Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
| | - Vitalii Kryvenko
- Member of the German Center for Lung Research (DZL), Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
| | - Khodr Tello
- Member of the German Center for Lung Research (DZL), Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
| | - Susanne Herold
- Member of the German Center for Lung Research (DZL), Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
| | - Rory E. Morty
- Member of the German Center for Lung Research (DZL), Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Department of Lung Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Friedrich Grimminger
- Member of the German Center for Lung Research (DZL), Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Institute for Lung Health (ILH), Giessen, Germany
| | - Laura A. Dada
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Werner Seeger
- Member of the German Center for Lung Research (DZL), Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
- Department of Lung Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- Institute for Lung Health (ILH), Giessen, Germany
| | - Jacob I. Sznajder
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - István Vadász
- Member of the German Center for Lung Research (DZL), Department of Internal Medicine, Justus Liebig University Giessen, Universities of Giessen and Marburg Lung Center (UGMLC), Giessen, Germany
- The Cardio-Pulmonary Institute (CPI), Giessen, Germany
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7
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Kryvenko V, Wessendorf M, Tello K, Herold S, Morty RE, Seeger W, Vadász I. Hypercapnia-induces IRE1α-driven Endoplasmic Reticulum-associated Degradation of the Na,K-ATPase β-subunit. Am J Respir Cell Mol Biol 2021; 65:615-629. [PMID: 34192507 DOI: 10.1165/rcmb.2021-0114oc] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Acute respiratory distress syndrome (ARDS) is often associated with elevated levels of CO2 (hypercapnia) and impaired alveolar fluid clearance. Misfolding of the Na,K-ATPase (NKA), a key molecule involved in both alveolar epithelial barrier tightness and in resolution of alveolar edema, in the endoplasmic reticulum (ER) may decrease plasma membrane (PM) abundance of the transporter. Here, we investigated how hypercapnia affects the NKA β-subunit (NKA-β) in the ER. Exposing murine precision-cut lung slices (PCLS) and human alveolar epithelial A549 cells to elevated CO2 levels led to a rapid decrease of NKA-β abundance in the ER and at the cell surface. Knockdown of ER alpha-mannosidase I (MAN1B1) and ER degradation enhancing alpha-mannosidase like protein 1 by siRNA or treatment with the MAN1B1 inhibitor, kifunensine rescued loss of NKA-β in the ER, suggesting ER-associated degradation (ERAD) of the enzyme. Furthermore, hypercapnia activated the unfolded protein response (UPR) by promoting phosphorylation of inositol-requiring enzyme 1α (IRE1α) and treatment with a siRNA against IRE1α prevented the decrease of NKA-β in the ER. Of note, the hypercapnia-induced phosphorylation of IRE1α was triggered by a Ca2+-dependent mechanism. Additionally, inhibition of the inositol trisphosphate receptor decreased phosphorylation levels of IRE1α in PCLS and A549 cells, suggesting that Ca2+ efflux from the ER might be responsible for IRE1α activation and ERAD of NKA-β. In conclusion, here we provide evidence that hypercapnia attenuates maturation of the regulatory subunit of NKA by activating IRE1α and promoting ERAD, which may contribute to impaired alveolar epithelial integrity in patients with ARDS and hypercapnia.
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Affiliation(s)
- Vitalii Kryvenko
- Justus Liebig University, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Department of Internal Medicine, Giessen, Germany.,The Cardio-Pulmonary Institute, Giessen, Germany
| | - Miriam Wessendorf
- Justus Liebig University, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Department of Internal Medicine, Giessen, Germany
| | - Khodr Tello
- Justus Liebig University, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Department of Internal Medicine, Giessen, Germany.,The Cardio-Pulmonary Institute, Giessen, Germany
| | - Susanne Herold
- Justus Liebig University, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Department of Internal Medicine, Giessen, Germany.,The Cardio-Pulmonary Institute, Giessen, Germany
| | - Rory E Morty
- Justus Liebig University, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Department of Internal Medicine, Giessen, Germany.,The Cardio-Pulmonary Institute, Giessen, Germany.,Max-Planck-Institute for Heart and Lung Research, Department of Lung Development and Remodeling, Bad Nauheim, Germany
| | - Werner Seeger
- Justus Liebig University, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Department of Internal Medicine, Giessen, Germany.,The Cardio-Pulmonary Institute, Giessen, Germany.,Max-Planck-Institute for Heart and Lung Research, Department of Lung Development and Remodeling, Bad Nauheim, Germany.,Justus Liebig University, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Department of Internal Medicine, Giessen, Germany
| | - István Vadász
- Justus Liebig University, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research, Department of Internal Medicine, Giessen, Germany.,The Cardio-Pulmonary Institute, Giessen, Germany;
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8
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Kryvenko V, Vagin O, Dada LA, Sznajder JI, Vadász I. Maturation of the Na,K-ATPase in the Endoplasmic Reticulum in Health and Disease. J Membr Biol 2021; 254:447-457. [PMID: 34114062 PMCID: PMC8192048 DOI: 10.1007/s00232-021-00184-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/08/2021] [Indexed: 12/11/2022]
Abstract
Abstract The Na,K-ATPase establishes the electrochemical gradient of cells by driving an active exchange of Na+ and K+ ions while consuming ATP. The minimal functional transporter consists of a catalytic α-subunit and a β-subunit with chaperon activity. The Na,K-ATPase also functions as a cell adhesion molecule and participates in various intracellular signaling pathways. The maturation and trafficking of the Na,K-ATPase include co- and post-translational processing of the enzyme in the endoplasmic reticulum (ER) and the Golgi apparatus and subsequent delivery to the plasma membrane (PM). The ER folding of the enzyme is considered as the rate-limiting step in the membrane delivery of the protein. It has been demonstrated that only assembled Na,K-ATPase α:β-complexes may exit the organelle, whereas unassembled, misfolded or unfolded subunits are retained in the ER and are subsequently degraded. Loss of function of the Na,K-ATPase has been associated with lung, heart, kidney and neurological disorders. Recently, it has been shown that ER dysfunction, in particular, alterations in the homeostasis of the organelle, as well as impaired ER-resident chaperone activity may impede folding of Na,K-ATPase subunits, thus decreasing the abundance and function of the enzyme at the PM. Here, we summarize our current understanding on maturation and subsequent processing of the Na,K-ATPase in the ER under physiological and pathophysiological conditions. Graphic Abstract ![]()
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Affiliation(s)
- Vitalii Kryvenko
- Department of Internal Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus Liebig University, Klinikstrasse 33, 35392, Giessen, Germany.,The Cardio-Pulmonary Institute (CPI), Giessen, Germany
| | - Olga Vagin
- Department of Physiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA, USA.,Veterans Administration Greater Los Angeles Healthcare System, Los Angeles, CA, USA
| | - Laura A Dada
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - István Vadász
- Department of Internal Medicine, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus Liebig University, Klinikstrasse 33, 35392, Giessen, Germany. .,The Cardio-Pulmonary Institute (CPI), Giessen, Germany.
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9
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Masterson C, Horie S, McCarthy SD, Gonzalez H, Byrnes D, Brady J, Fandiño J, Laffey JG, O'Toole D. Hypercapnia in the critically ill: insights from the bench to the bedside. Interface Focus 2021; 11:20200032. [PMID: 33628425 PMCID: PMC7898152 DOI: 10.1098/rsfs.2020.0032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2020] [Indexed: 01/16/2023] Open
Abstract
Carbon dioxide (CO2) has long been considered, at best, a waste by-product of metabolism, and at worst, a toxic molecule with serious health consequences if physiological concentration is dysregulated. However, clinical observations have revealed that 'permissive' hypercapnia, the deliberate allowance of respiratory produced CO2 to remain in the patient, can have anti-inflammatory effects that may be beneficial in certain circumstances. In parallel, studies at the cell level have demonstrated the profound effect of CO2 on multiple diverse signalling pathways, be it the effect from CO2 itself specifically or from the associated acidosis it generates. At the whole organism level, it now appears likely that there are many biological sensing systems designed to respond to CO2 concentration and tailor respiratory and other responses to atmospheric or local levels. Animal models have been widely employed to study the changes in CO2 levels in various disease states and also to what extent permissive or even directly delivered CO2 can affect patient outcome. These findings have been advanced to the bedside at the same time that further clinical observations have been elucidated at the cell and animal level. Here we present a synopsis of the current understanding of how CO2 affects mammalian biological systems, with a particular emphasis on inflammatory pathways and diseases such as lung specific or systemic sepsis. We also explore some future directions and possibilities, such as direct control of blood CO2 levels, that could lead to improved clinical care in the future.
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10
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Kryvenko V, Vadász I. Molecular mechanisms of Na,K-ATPase dysregulation driving alveolar epithelial barrier failure in severe COVID-19. Am J Physiol Lung Cell Mol Physiol 2021; 320:L1186-L1193. [PMID: 33689516 PMCID: PMC8238442 DOI: 10.1152/ajplung.00056.2021] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A significant number of patients with coronavirus disease 2019 (COVID-19) develop acute respiratory distress syndrome (ARDS) that is associated with a poor outcome. The molecular mechanisms driving failure of the alveolar barrier upon severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remain incompletely understood. The Na,K-ATPase is an adhesion molecule and a plasma membrane transporter that is critically required for proper alveolar epithelial function by both promoting barrier integrity and resolution of excess alveolar fluid, thus enabling appropriate gas exchange. However, numerous SARS-CoV-2-mediated and COVID-19-related signals directly or indirectly impair the function of the Na,K-ATPase, thereby potentially contributing to disease progression. In this Perspective, we highlight some of the putative mechanisms of SARS-CoV-2-driven dysfunction of the Na,K-ATPase, focusing on expression, maturation, and trafficking of the transporter. A therapeutic mean to selectively inhibit the maladaptive signals that impair the Na,K-ATPase upon SARS-CoV-2 infection might be effective in reestablishing the alveolar epithelial barrier and promoting alveolar fluid clearance and thus advantageous in patients with COVID-19-associated ARDS.
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Affiliation(s)
- Vitalii Kryvenko
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany.,The Cardio-Pulmonary Institute (CPI), Giessen, Germany
| | - István Vadász
- Department of Internal Medicine, Justus Liebig University, Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Giessen, Germany.,The Cardio-Pulmonary Institute (CPI), Giessen, Germany
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11
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Abstract
Carbon dioxide (CO2), a primary product of oxidative metabolism, can be sensed by eukaryotic cells eliciting unique responses via specific signalling pathways. Severe lung diseases such as chronic obstructive pulmonary disease are associated with hypoventilation that can lead to the elevation of CO2 levels in lung tissues and the bloodstream (hypercapnia). However, the pathophysiological effects of hypercapnia on the lungs and specific lung cells are incompletely understood. We have recently reported using combined unbiased molecular approaches with studies in mice and cell culture systems on the mechanisms by which hypercapnia alters airway smooth muscle contractility. In this review, we provide a pathophysiological and mechanistic perspective on the effects of hypercapnia on the lung airways and discuss the recent understanding of high CO2 modulation of the airway contractility.
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Affiliation(s)
- Masahiko Shigemura
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, IL, USA
| | - Jacob I Sznajder
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, IL, USA
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12
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Balnis J, Lee CG, Elias JA, Jaitovich A. Hypercapnia-Driven Skeletal Muscle Dysfunction in an Animal Model of Pulmonary Emphysema Suggests a Complex Phenotype. Front Physiol 2020; 11:600290. [PMID: 33192616 PMCID: PMC7658396 DOI: 10.3389/fphys.2020.600290] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 10/08/2020] [Indexed: 12/11/2022] Open
Abstract
Patients with chronic pulmonary conditions such as chronic obstructive pulmonary disease (COPD) often develop skeletal muscle dysfunction, which is strongly and independently associated with poor outcomes including higher mortality. Some of these patients also develop chronic CO2 retention, or hypercapnia, which is also associated with worse prognosis. While muscle dysfunction in these settings involve reduction of muscle mass and disrupted fibers’ metabolism leading to suboptimal muscle work, mechanistic research in the field has been limited by the lack of adequate animal models. Over the last years, we have established a rodent model of COPD-induced skeletal muscle dysfunction that allowed a disaggregated interrogation of the cellular and physiological effects driven by COPD from the ones unique to hypercapnia. We found that while COPD and hypercapnia synergistically contribute to muscle atrophy, they are antagonistic processes regarding fibers respiratory capacity. We propose that AMP-activated protein kinase (AMPK) is a crucial regulator of CO2 signaling in hypercapnic muscles, which leads to both net protein catabolism and improved mitochondrial respiration to support a transition into a substrate-rich, fuel-efficient metabolic mode that allows muscle cells cope with the CO2 toxicity.
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Affiliation(s)
- Joseph Balnis
- Division of Pulmonary and Critical Care Medicine, Albany Medical College, Albany, NY, United States.,Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, United States
| | - Chun Geun Lee
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, United States
| | - Jack A Elias
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI, United States
| | - Ariel Jaitovich
- Division of Pulmonary and Critical Care Medicine, Albany Medical College, Albany, NY, United States.,Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, United States
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Hypercapnia: An Aggravating Factor in Asthma. J Clin Med 2020; 9:jcm9103207. [PMID: 33027886 PMCID: PMC7599850 DOI: 10.3390/jcm9103207] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/01/2020] [Accepted: 10/02/2020] [Indexed: 02/06/2023] Open
Abstract
Asthma is a common chronic respiratory disorder with relatively good outcomes in the majority of patients with appropriate maintenance therapy. However, in a small minority, patients can experience severe asthma with respiratory failure and hypercapnia, necessitating intensive care unit admission. Hypercapnia occurs due to alveolar hypoventilation and insufficient removal of carbon dioxide (CO2) from the blood. Although mild hypercapnia is generally well tolerated in patients with asthma, there is accumulating evidence that elevated levels of CO2 can act as a gaso-signaling molecule, triggering deleterious effects in various organs such as the lung, skeletal muscles and the innate immune system. Here, we review recent advances on pathophysiological response to hypercapnia and discuss potential detrimental effects of hypercapnia in patients with asthma.
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